Fatty acid profiles of typical dietary lipids after gastrointestinal digestion and absorbtion: A combination study between in-vitro and in-vivo

The objective of the present study was to investigate the influences of dietary lipid composition on the gastrointestinal digestion and postprandial serum lipid profiles, and the connections between them. The in-vitro digestion results showed that maximum free fatty acid (FFA) release level of different lipid samples was PO (Palm oil) > RO (Rapeseed oil) > LINO (Linseed oil) > SO (Sunflower oil) > LO (Lard oil), and the first-order kinetics apparent rate constant was PO > SO ≈ RO > LO ≈ LINO, this may probably be ascribed to their specific lipid fatty acid composition and TAG structure. The individual FFA released during 240 min in-vitro digestion time was measured, and it showed that the release rate of short-chain saturated fatty acids (e.g. C16:0 in PO) were higher than the long-chain poly-unsaturated fatty acids (e.g. C18:3n-3 in LINO). Besides, the position of fatty acids within TAG molecules could also impose influences on the lipid hydrolysis process upon pancreas lipase in gastrointestinal tract using in-vitro digestion model. The postprandial serum fatty acid composition of the adult SD male rats were examined within 240 min after oral gavage administration, and the Pearson correlations between lipid fatty acid composition and the serum fatty acid profiles were analyzed. Certain correlations were summarized between lipid compositions (i.e. fatty acid composition and TAG structure), lipid digestion fates and serum fatty acid content in postprandial. The present work may provide some basic understandings of the connections among lipid compositions, lipid gastrointestinal digestion differences and the postprandial serum lipid profiles, and provide useful information about their nutritional and functional evaluation.